Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden, and it does disclose useful behavior: a fixed 7-day lookback, a hard cap of 5 results, and magnitude-based ranking. It says nothing about authentication, rate limits, freshness/latency, or what fields each quake record contains.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single short sentence with the most decision-relevant token ('FREE') front-loaded, then source, scope, and result shape. Efficient, though the 'FREE.' fragment is slightly clipped and the top-5 cap could read ambiguously as a parameter.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, no-output-schema tool, the description covers source, time window, result count, and ordering — enough to call it correctly. A brief note on returned fields or on how it differs from 'ga_week' is the only real gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters and schema coverage is 100%, so there is nothing to disambiguate; the description correctly adds no redundant parameter prose. The mention of 'top 5 by magnitude' usefully signals that the result cap and ordering are fixed rather than configurable.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States the resource (Geoscience Australia earthquakes), the time window (last 7 days), and the result shaping (top 5 by magnitude) — an agent knows exactly what comes back. It does not differentiate itself from the sibling 'ga_week', which plausibly covers the same source and period, so the agent cannot tell them apart from the description alone.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The leading 'FREE.' hints that cost should influence selection, but there is no explicit when-to-use, when-not-to-use, or pointer to 'ga_week' / 'region_search' as alternatives. Usage must be inferred entirely from the time-window and top-5 constraint.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.